1. Field of the Invention
The present invention relates to an optical device and in particular to a lighting and/or signaling system for an automotive vehicle, the system being equipped with such a device.
2. Description of the Related Art
A direction indicator light of an automotive vehicle serves to let the drivers of vehicles in nearby road traffic know that the driver wants to change direction. Correct and rapid perception of the indicator light is a key factor in road safety. It is known that a direction indicator light is a light that emits a flashing luminous signal in red or amber light, the color and how fast the light flashes being chosen to rapidly draw the attention of an observer to the emitted signal.
The use of a sequential direction indicator light (“tracer light”) allows the perceivability of such a signal to be increased and road safety to be improved. Specifically, the Human Visual System rapidly reacts to a perceived movement. In general, a moving light is perceived more rapidly than a changing color and even more rapidly than a flashing light.
The use of light-emitting diodes (LEDs) is increasingly advocated in the field of automotive vehicles as a way of providing luminous functions such as daytime running lights, signal lights, or for example direction indicator lights.
The use of light guides to guide the light emitted by an LED or a group of LEDs is also a measure applied in the luminous devices of automotive vehicles. This technique allows a high degree of flexibility to be obtained in the design of a headlamp, especially as regards the arrangement of the LEDs, the physical location of which crucially must not correspond to the location of the light spots that they are intended to produce. One light guide known in the prior art may be used to guide the light emitted by an LED mounted at a first end to a different second end. Alternatively, a slab light guide may be used in order to illuminate a strip, corresponding to the output of the guide, relatively uniformly using one or more LEDs.
As is known, it is possible to use light guides placed in a row to produce a sequential direction indicator. Each guide or guide portion corresponds to a division of the direction indicator and turning on the divisions one by one allows a sequential effect to be obtained.
It has been proposed, for example in patent document EP 2 541 128, which is equivalent to U.S. Pat. No. 8,888,343 and U.S. Patent Publication No. 2013/0003399, to use a plurality of light guides within a given optical device to produce a plurality of luminous functions of a lighting or signaling device of an automotive vehicle. The integration of a plurality of luminous functions, for example, a sequential direction indicator function and a daytime running light function, allows, on the one hand, the bulk in the restricted space afforded by a vehicle light to be decreased, and on the other hand, allows interesting optical signatures to be produced.
In the solution known from EP 2 541 128, a daytime running light function may be produced by a cylindrical light guide arranged behind an exit face of a slab guide, which may provide a direction indicator function. The intensity of the visible light flux emitted by the first light guide may however be decreased by the passage of the emitted rays through part of the second guide.
Patent document DE 10 2013 104 169 proposes to place a first light guide having a cylindrical exit face in front of a slab guide. In this arrangement, the intensity of light flux emitted by the slab guide is decreased by the passage of the emitted rays through part of the first guide.